Landing mat



Jan. 26, 1960 M. F. MEISSNER ,9

LANDING MAT Filed Oct. 15. 1953 4 Sheets-Sheet 1 FIG. I.

INVENTOR. MILTON F. MEISSNER ATTORNE Y Jan. 26, 1960' M. F. MEISSNER 2,922,344

LANDING MAT Filed Oct. 13. 1953 4 Sheets-Sheet 2 I I A 1/ /r 1 r I 44 as 42 as 40 34 i as v INVENTOR. MILTON F. MEISSNER A TTORNE Y Jan. 26, 1960 M. F. MEISSNER 2,922,344

' LANDING MAT Filed Oct. 13. 1953 4 Sheets-Sheet 3 INVENTOR. MILTON F. MEISSNER ATTORNEY Jan. 26, 1960 M. F. MEISSNER 2,922,344

LANDING MAT Filed o t; 15. 1953 4 Sheets-Sheet 4 Flag."

2 63 00050000000 ooeooog c oofl INVENTOR. MILTON F. MEISSNER I a6 ATTORNEY United tatesPatent O LANDING MAT Milton F. Meissuer, La Due, Mo., assignor to Olin Mathieson Chemical Corporation, a corporation of Virginia Application October 13, 1953, Serial No. 385,778

3 Claims. (Cl. 94-11) This invention relates to a landing strip or pavement mat structure and method of erection of it and more particularly to a sheet metal mat suitable for being laid down upon terrain not quite satisfactory in itself for a landing field and adaptable to the formation of a dependable, sturdy landing surface for aircraft with a minimum of delay, labor and auxiliary equipment.

Portable emergency land mats heretofore tried consist of a steel wire open mesh structure such as wire fencing of'the heavy chain link type. On account of the open mesh structure involved in such foraminous articles, one disadvantage of such mats has been the great bulk occupied in storage and transportation as compared to the relatively small amount of material and usable surface carried. Such bulky materials require extensive transportation facilities. Moreover, the openings eventually permit bogging down of such mats when they are applied over mud or other land subject to the gathering of surface waters. This disadvantage is unavoidable even when such mats have been laid over ideal dry terrain in the event of either a prolonged or unusually heavy fall of rain. Precipitation in cold weather resulting in icing conditions or a heavy snow likewise renders this type of rnat entirely useless or extremely dangerous.

Another disadvantage of an open mesh type of landing mat is that unless the individual filaments are of considerable thickness, which adds both weight and bulk to the mat, the mat is not quite 'as strong and durable as desired so as to be capable of withstanding the force of impact with the landing wheels of descending aircraft. In fact, if wires of this type of mat are broken and pro- I trude it will be readily understood that they may operate to puncture or contribute to the puncture of the air tires of landing gear and produce a disaster.

It is therefore an object of the present invention to provide a transportable landing strip element which occupies a minimum of bulk when in storage or transportation until in actual use as landing pavement. Another object is the provision of a landing mat element of maximum strength but of minimum weight and bulk. Another object is the erection of a reinforced landing strip of suitably high strength and adequate rigidity from a sheet metal strip material originally solid but relatively thin and pliant so as to facilitate packing, transportation and handling in the field. A still further object is to provide a metal landing strip relatively free from the danger of bogging down over water softened terrain. Still another object is the provision of an inflatable mat structure internally cavitated for strength and for permitting passage of heated fluid in conductive relation with the mat, if necessary, in order to maintain the landing strip free of snow and ice in frigid climates.

The present invention will be understood more clearly from the following description of several specific embodiments taken together with the accompanying drawing in h a Figure l is aninterrupted plan view of an uninflated sheet metal mat element in accordance with one embodiice ment of the invention showing in phantom the layout of I one stratum of the parallel bands along which the metal is internally parted so as to adapt it for inflation;

Figure 2 is a cross sectional view of a portion of the embodiment of Figure 1 taken on line IIH transversely with respect to the length of the strip;

Figure 3 is a cross sectional view of the configuration assumed by the portion of Figure 2 after inflation;

Figure 4 is an interrupted view of an uninflated sheet metal mat element showing in phantom a modification of the pattern of parallel bands of Figure 1;

Figure 5 is a fragmentary cross sectional view of another and preferred embodiment taken prior to inflation and corresponding to the partial sectional view of Figure 2;

Figure 6 is a fragmentary cross sectional and perspective view showing both surface and interior mat structural details of the embodiment of Figure 5 after inflation at one level of pressure;

Figure 7 is a fragmentary cross sectional view of the inflated shape of a modified embodiment similar to the embodiment of Figure-5 assumed at another level of inflation pressure;

Figure 8 is a perspective view of the mat stripmaterial of this inventionin the coil form preferred for transportation and handling. One end is shown unwound'so as to better illustrate the end structure, and

Figure 9 is a plan view of a representative portion of a runway comprising a plurality of landing strip elements connected together after having been transported by air to the landing site in the form of predominantly solid coils.

The embodiment of Figures 1, 2 and 3 is the simplest and consists of an elongated flat sheet of metal of uniform thickness and includes in the-single body of the sheet between lateral edge portions 3 and 23 and below the upper exterior surface forming half 1, Figure 1, a pattern of many closely spaced parallel areas of internal metal separation or parting areas 4, 6, 8, 10, 26, 28, and 30 the adjacent ones of which are separated from each other by unparted areas 5, 7, 9, 27 and 29 respectively. The separation of parting areas 4, 6, 8, 10, 26, 28 and 30 form bands or stripes running substantially the entire length of the longest dimension of the strip from adjacent the end portion 11 to adjacent the end portion 16; and each is made up of juxtaposed interior surfaces a typical pair of which are 31 and 32, Fig. 2, which together with a thin layer of interposed weld preventing composition constitute a typical parting area 4. The separation areas 4, 6, 8, 10 26, 28, and 30 are disposed in a single stratum midway between the upper outer surface forming half 1 and the lower outer surface forming half 2, Figure 2. Within the stratum each of the separationareas is spaced from adjacent such areas by an unparted area such as 5, 7, 9, 27 and 29 each of the latter of which is merely a continuation of and integral with the halves 1 and 2. The width of each unparted area is only a small fraction, less than one half, of the width of a separation area. In general, the joined unparted areas must be of such width as to constitute on inflation of the strip only a minor portion of the projected plan area of the strip but must be broad enough to resist tearing under the forces. of inflation. Satisfactory relative widths of the parted and .unparted areas will vary with the composition and gage of the sheet metal as well as the inflation pressure to be employed. In the embodiment shown in Figure 2 the joined areas 5, 7 and 9 are of a width about a fourth the width of the separation areas 4, 6, 8 and 10.

To permit application of inflation pressure to all of the longitudinally extending parted areas or bands 4, 6, 8, 10, 26, 28 and 30 of this embodiment there is provided adjacent one of the ends 11 of the strip, Figure 1, a very narrow transverse parted area 12 which upon application of fluid pressure therein constitutes a passageway common to one of the ends of all of the longitudinal parted areas and communicates with the exterior of the strip by means of opening 13 running to edge 11. A piece of tubing 14 is fixed in opening 13 by welding or brazing and has an end connection 15 for attachment to the delivery side of a suitable fluid pump. Adjacent the other end 16 of the sheet metal strip the parting bands or stripe each terminate short of end 16 to form end closures for containment of fluid pressure during inflation. However, where it is desired that heating fluid be afterward circulated through the internal cavities formed by inflation the end structure at end 16 may be identical with that at end 11 except that the fluid pressure connection at 16 may be initially sealed by any suitable means such as a pipe plug which may later be removed to permit an outlet connection to be made at end 16.

Upon inflation the cross sectional portion illustrated in Figure 2 assumes the shape shown in Figure 3. Pressure acting on the internal juxtaposed surfaces has transformed the thin separation areas 4, 6, 8 and 10 into internal tubular cavities 17, 18, 19 and 20 respectively. The upper surface forming half 1 of the strip develops a plurality of long ribs or protruding corrugations 21 while the lower surface forming half 2 develops corrugations 22. Remaining between corrugations 21 and 22 are the narrow unparted sections 5, 7, and 9 which constitute but a small part of the area of the inflated sheet metal element. The flexural strength of the inflated surface corrugated strip exceeds that of a conventional solid strip of metal having the same gage as the uninflated sheet metal element described.

The lateral edge portions of the strip 3 and 23 are provided respectively with an equally spaced arrangement of perforations 24 and 25. These serve to adapt the landing mat strip for joining with other like strips for the purpose of building a mat structure of any desired ground coverage.

In order to obtain a still further improvement in flexural rigidity by inflation of the landing mat sheet metal element of this invention, it is desirable that there be a plurality of strata, preferably two, of alternate parted and unparted elongated areas having the parallel band design herein disclosed. Two strata are preferred inasmuch as the advance from one stratum to two strata provides a large increase in rigidity with little increase in complexity of construction.

The preferred embodiment shown in Figure includes two strata of parting bands and is illustrative of the desired arrangement whenever two or more such strata are involved. Except for a solid lateral marginal or edge portion such as 33 on each side, the separation bands are arranged across the width of the strip with the pattern in one stratum offset with respect to the pattern in the adjacent stratum by an amount that places the line of longitudinal bisection of one given band or stripe in coincidence with the line of longitudinal bisection of the unparted area in the adjacent stratum intermediate the two neighboring bands in the adjacent stratum, both of which overlaps the given band in part. The bands such as 35, 37 and 39 of one stratum partially overlap the bands 34, 36 and 38 of the other stratum in such a way that, when the group of separation bands are arranged in the order 34, 35, 36, 37, 38 and 39, alternate bands are all disposed in one of the strata while the other bands are all disposed in the other stratum in evenly staggered relationship with the bands of the first stratum. By evenly staggered relationship is meant that the unparted areas of one stratum adjoin the longitudinal midsection of the parted areas of adjacent strata. Specifically, in the embodiment of Figure 5, typical unparted area 41 of the upper stratum adjoins the midsection of the band 4 36 of the lower stratum, while unparted area 42 of the lower stratum adjoins the center of band 37 of the upper stratum.

It is to be observed that each of the unparted areas 40, 41, 42, 43 and 44 are of equal width but considerably narrower than any of the bands 34, 35, 36, 37, 38 and 39 all of which are also of substantially equal width. For example, bands along Which the metal is parted because of the presence of a layer of weld preventing material may each have a width of about of an inch while adjacent bands in the same stratum are spaced from each other by an unparted area having a width of about onecighth of an inch. With these relative proportions the thickness of metal between strata and also the thickness of metal between the exterior of the sheet may be of the order of 0.020 of an inch.

Having in each stratum the pattern shown in Figure 1, the sheet of Figure 5 assumes upon inflation the cellular structure, shown in Figure 6, which develops as fluid pressure is applied within and along the bands of metal separation 34, 35, 36, 37, 38 and 39 against the internal juxtaposed. surfaces of each band. Inflation produces upon both the exterior surfaces of the sheet metal strip of this embodiment corrugations consisting of the arched protrusions 45 and 46 running lengthwise of the strip. Between each such arched protrusion there is formed a narrower arch of less curvature but of thickness double that of arches 45 and 46. These intermediate arches constitute the base of troughs between the surface protrusions and are formed of the unparted areas 40, 41, 42, 43', and 44. Internally of the strip there are formed webs 47. The forces generated on the metal by inflation pressure within the cavitated sheet structure produce an appreciable strengthening by work hardening arched sections 45 and 46 and the internal web sections 47.

With some modification of the two strata basic strip of Figure 5 and by means of a still further application of inflation pressure at a higher pressure there is obtainable the cross sectional structure illustrated in Figure 7 rather than that of Figure 6. This embodiment is characterized by a middle or interior component strip having a thickness somewhat greater than that of the two exterior component strips. Upon inflation at a pressure sutficiently great there is developed a series of substantially semicircular arch-like externally protruding corrugations and 146 together with an internal corrugated section forming thick webs 147 substantially normal to the plane of the landing mat strip and also heavy connecting sections 140, 141, 142, 143 and 144. This embodiment of the mat structure of the present invention is designed for heavy duty operations particularly when the design of the band pattern follows that of Figure 4.

As in the previous embodiments each lateral edge 33 of the embodiment of Figure 5 is provided with a series of perforations 48 as shown in Figure 6.

As mentioned hereinbefore the preferred form of the uninflated landing mat sheet metal strip is the coil form illustrated in Figure 8 irrespective of whether the design of the separation bands be that of Figure 1 or Figure 4 and irrespective of whether the number of strata be one as in Figure 2 or two as in Figure 5. In the coil form the landing strip consists of the convolutely wound roll 49, the tail or end section 50 provided with the pressure inlet tube 53 and the tube connection 54. As is clearly illustrated on the unwound end section 50 of Figure 8, the lateral edges of the sheet metal landing strip are perforated to provide a series of fastening holes 51 and 52. By laying down the rolls 49 and unwinding each so that the lateral edge of one strip overlaps a lateral edge of an adjacent strip already laid down and so that the holes match up, a secure lap joint is formed with the use of suitable fasteners such as explosive actuated rivets. Alternately the lateral margins may be left unperforated and a lap joint may be readily accomplished by explosive driven studs of the projectile type.

As shown in Figure 9, the transported coils are unrolled to form elements 60, 70, 80, 90, et cetera each inflated to form surface corrugations 66, 76, 86, 96 et cetera respectively. Each has suitable fluid connection and injection means, such as inlet tubes 63, 73, 83, 93 et cetera, respectively, with couplings 64, 74, 84, 94 et cetera. Where series connection is desired as shown the elements may also be provided with an outlet tube such as 163, 173, 183 et cetera. Elements 60 and 70 are joined by a series of explosive fasteners 100. Elements 70 and 80 are joined by fasteners 101 and elements 80 and 90 by fasteners 102. While series connection is shown, it will be understood that separate connection may be made to each from an individual fluid source independently of adjoining elements.

The special partially laminated or parted sheet metal strip employed for the purposes of this invention is essentially a unitary or single body of metal preformed by hot pressure welding of two or more component sheets of the same metal which in the process have been so united by pressure welding at elevated temperature as to have lost their separate identity as components except in those areas between sheets where a coating of weld preventing material has been disposed in a pattern of the type described herein. By means of an adequate rolling reduction of an assembly of superposed component metal layers heated to an elevated temperature usually above the recrystallization temperature of the metal, there is obtained a substantially complete erasure of the interface between component layers. Such pressure welded strip is preferred over strip formed by other methods such as soldering or spot welding because of the superior strength obtainable and necessary in the strip to withstand inflation pressures that might otherwise bring about complete separation of the distinct components of strip made by soldering or brazing, for example.

A suitable stop-off composition, for example, is one composed of about 40 percent calcium carbonate in the form of ground oyster shell having a granulation of less than 325 mesh, about 13 percent of colloidal graphite, about 1 percent wetting agent and the balance water. However any heat resistant or refractory material or mixture may be employed so long as it serves to prevent welding between sheets in the area coated and is at the same time capable of being elongated to a very thin interfacial layer with the metal during reduction by rolling without producing discontinuity in the pattern and without flowing uncontrollably under pressure.

It will be appreciated that the landing mat elements described may be utilized to great advantage particularly in military operations since each element is readily transportable and easily manipulable for assembly and erection. Occupying a minimum of space during storage and transport, each element provides a maximum of ground coverage and strength as compared to the weight of material involved. While the landing strip may consist of any suitable metal such as soft, mild steel or an alloy of copper, it is preferred that it be made of a light metal such as aluminum or magnesium or alloys thereof so as to take advantage of the lightness of the metal and adapt the mat for transportation by air to proposed landing sites otherwise either inaccessible or reached with considerable difficulty by other modes of transportation. It will be appreciated that airfield runways of a variety of sizes may be conveniently and quickly assembled using the coiled landing mat element described herein.

Since many other embodiments of this invention may occur to those skilled in the art, it is to be understood that the foregoing is intended as illustrative of preferred embodiments and not as a limitation of the scope of the present invention except as set forth in the appended claims.

What is claimed is:

l. A landing field comprising a plurality of mats laid side by side and connected together along their edges, each of said mats comprising superimposed sheets of thin sheets of metal welded together in substantially parallel rows with the intermediate portions therebetween being unwelded, said sheets being further welded coextensively with said parallel rows transversely at the ends of said intermediate portions so that said intermediate portions form tubes when subjected to fluid pressure, said tubes in each mat communicating with each other by means of a similar transverse connecting tube, said connecting tube being provided with fittings adapted to be attached to a source of fluid pressure whereby said tubes are inflated to form corrugations on the upper and lower surfaces thereof.

2. The landing field of claim 1 wherein said tubes contain fluid under pressure.

3. The method of constructing an air field comprising in combination the steps of transporting by air to proposed aircraft landing sites a plurality of convolutely wound coils of prefabricated mats, each of said mats comprising superimposed sheets of thin sheets of metal welded together in substantially parallel rows with the intermediate portions therebetween being unwelded, said sheets being further welded coextensively with said parallel rows transversely at the ends of said intermediate portions so that said intermediate portions form tubes when subjected to fluid pressure, said tubes in each mat communicating with each other by means of a similar transverse connecting tube, said connecting tube being provided with a fitting adapted to be attached to a source of fluid pressure for inflation of said tubes, unrolling said coils at said landing site to lay down said mats in side by side relationship to each other, connecting the edge portions of said mats to the edge portions of adjacent mats, connecting said mats by means of said fitting to a source of fluid pressure, and introducing fluid pressure through said fitting into said unwelded portions to inflate said unwelded portions so as to form tubes and surface corrugations on the upper and lower surfaces thereof.

References Cited in the file of this patent UNITED STATES PATENTS 511,472 Sumovski Dec. 26, 1893 2,212,481 Sendzimir Aug. 20, 1940 2,342,773 Wellman Feb. 29, 1944 2,375,334 Valyi et a1. May 8, 1945 2,478,993 Wing Aug. 16, 1949 2,639,650 Robishaw May 26, 1953 2,662,273 Long Dec. 15, 1953 2,690,002 Grenell Sept. 28, 1954 2,740,188 Simmons Apr. 13, 1956 2,766,514 Adams Oct. 16, 1956 

